Teenage twin sisters and their father have been shot and killed in what police have described as a 'domestic related incident' at their home.
The 16-year-old girls were found by police at their luxury condominium home in St Charles, Illinois, reports Associated Press.
Emergency services were alerted after they received reports of gunshots from inside the home.
Police have named the twin sisters as Brittany and Tiffany Coffland and their father as 48-year-old Randall R. Coffland.
According to investigators, all three had reportedly been shot in the head and a handgun was found at the scene near Mr Coffland.
The mother and wife of the deceased, 46-year-old Anjum Coffland, has been hospitalised with gunshot wounds.
Police say Anjum and Randall were married but living at separate addresses.
It is understood that she is currently in a stable condition.